Inverse element - Jamb Mathematics Past Questions and Answers

Question 1:

• JAMB 1979

The mean of the numbers 1.2, 1.0, 0.9, 1.4, 0.8, 0.8, 1.2 and 1.1 is

A. 1.5
B. 0.8
C. 1.0
D. 1.02
E. 1.05

Question 2:

• JAMB 2017

The operation * on the set R of real number is defined by x * y = 3x + 2y − 1, find 3* − 1

A. 9
B. - 9
C. 6
D. - 6

Question 3:

• JAMB 1994

\(\begin{array}{c|c} \oplus mod 10 & 2 & 4 & 6 & 8 \\ \hline 2 & 4 & 8 & 2 & 6 \\4 & 8 & 6 & 4 & 2\\ 4 & 8 & 6 & 4 & 2\\ 6 & 2 & 4 & 6 & 8\\ 8 & 6 & 2 & 8 & 4\end{array}\)
The multiplication table above has modulo 10 on the set S = (2, 4, 6, 8). Find the inverse of 2

A. 2
B. 4
C. 6
D. 8

Question 4:

• JAMB 2000

Find the inverse of p under the binary operation * defined by p*q = p + q - pq, where p and q are real numbers and zero is the identity

A. P
B. P -1
C. P/(p-1)
D. P/(p+1)

Question 5:

• JAMB 2001

An operation * is defined on the set of real numbers by a*b = a + b + 1. If the identity elements is -1, find the inverse of the element 2 under *.

A. 4
B. Zero
C. -2
D. -4